Red Sub (typically styled RedSub) is a bass-focused house brand of Gear4Music, the UK musical instrument retailer based in York. Launched in 2012, the brand develops budget- and mid-priced bass guitars, bass amplifiers, and speaker cabinets sold primarily through Gear4Music's own retail channels rather than the independent dealer network used by larger bass brands.

The lineup leans toward designs that aim to deliver more specialist features at accessible price points. Notable models include the Coliseum series of solid-body basses (offered in 4-, 5-, and fanned-fret multi-scale versions), the Infinity Fan Fret multi-scale bass, and the HB semi-hollow bass, which takes visual cues from short-scale hollowbody designs of the 1960s. The amplifier and cabinet range covers small practice combos through to gigging-level solid-state heads and 4x10/1x15 cabinets.

Discussion of the brand on bass-focused communities such as TalkBass and Basschat tends to position RedSub as a value-oriented option, particularly for players wanting fanned-fret or extended-range basses without paying boutique prices. The brand has limited standalone marketing presence and is generally encountered as part of the wider Gear4Music catalog.

Red Sub has 2 products cataloged on Equipboard, including Overdrive Effects Pedals and Bass Combo Amplifiers.